Research On High Power IGBT Drive Circuit

High-power IGBT(Insulated Gate Bipolar Transistor),as the core device of power electronic equipment,combines the advantages of power MOSFET and GTR,and occupies a dominant position in the field of high voltage,high current and high frequency switch drivers.The drive circuit connects the switch drive circuit and the control circuit,which directly determines the switching performance of the high-power IGBT,which has an important impact on the system reliability,efficiency,and safety of the IGBT switch operation.This paper mainly combines the development and application status of high-power driver switching technology at home and abroad.Based on the study of signal isolation and power isolation,a high-power IGBT drive circuit with excellent switching performance and comprehensive protection functions is designed.The main research contents of this article are as follows:First,the basic structure of IGBT is introduced,and the static and dynamic operating characteristics of IGBT are analyzed.On the basis of careful study of the parameter changes at various stages of the IGBT switching process,the generation mechanism of IGBT static and dynamic anchoring effects is analyzed,and IGBT safety is proposed from this Work area(SOA).Secondly,the overall framework of the high-power IGBT drive circuit is introduced.A narrow pulse signal generation and elimination circuit is designed.In view of the insufficient transmission capacity of traditional optocoupler isolation,a lowlatency high-frequency optocoupler signal isolation circuit is designed.The half-bridge power isolation circuit with high isolation level is studied and simulated.Thirdly,on the basis of studying the influence of gate resistance on IGBT switching performance during the IGBT switching process,a variable gate resistance driving scheme is proposed.An analog feedback circuit based on the induced electromotive force VEe generated by the parasitic inductance LEe when the collector current changes as a feedback signal was studied.A variable gate resistance soft with high accuracy,low delay and simple structure was designed Switch drive control circuit.Build a Hefner simulation model in Saber software and verify the reliability of the driving scheme.Finally,in order to be able to correctly identify the IGBT fault status and protect it in time,the overcurrent protection circuit,overvoltage protection circuit,overtemperature protection circuit and undervoltage protection circuit with high detection accuracy were studied and improved,and the fault blocking circuit pair was designed.The IGBT is blocked in milliseconds under the fault state and soft-switched off to avoid faults such as the shut-off effect,and the reliability of the protection circuit is verified in Saber software.